| /******************************************************************************* |
| * Copyright (c) 2005, 2010 Oracle. All rights reserved. |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Public License v1.0, which accompanies this distribution |
| * and is available at http://www.eclipse.org/legal/epl-v10.html. |
| * |
| * Contributors: |
| * Oracle - initial API and implementation |
| ******************************************************************************/ |
| package org.eclipse.jpt.common.core.utility; |
| |
| import org.eclipse.wst.validation.internal.provisional.core.IMessage; |
| |
| /** |
| * A text range defines the offset into, length of, and line of a piece |
| * of text. |
| * |
| * Provisional API: This interface is part of an interim API that is still |
| * under development and expected to change significantly before reaching |
| * stability. It is available at this early stage to solicit feedback from |
| * pioneering adopters on the understanding that any code that uses this API |
| * will almost certainly be broken (repeatedly) as the API evolves. |
| * |
| * This interface is not intended to be implemented by clients. |
| * |
| * @version 2.0 |
| * @since 2.0 |
| */ |
| public interface TextRange { |
| |
| /** |
| * Returns the offset of the text. |
| * |
| * @return the offset of the text |
| */ |
| int getOffset(); |
| |
| /** |
| * Return the length of the text. |
| */ |
| int getLength(); |
| |
| /** |
| * Return whether the range includes the character at the specified index. |
| */ |
| boolean includes(int index); |
| |
| /** |
| * Return whether the range touches an insertion cursor at the |
| * specified index. |
| */ |
| boolean touches(int index); |
| |
| /** |
| * Return the line number of the text. |
| */ |
| int getLineNumber(); |
| |
| /** |
| * Return true if the offsets and lengths are the same. |
| */ |
| boolean equals(Object obj); |
| |
| /** |
| * Return a hash code that corresponds to the #equals() contract. |
| */ |
| int hashCode(); |
| |
| |
| /** |
| * Empty implementation of text range. |
| */ |
| final class Empty implements TextRange { |
| public static final TextRange INSTANCE = new Empty(); |
| public static TextRange instance() { |
| return INSTANCE; |
| } |
| // ensure single instance |
| private Empty() { |
| super(); |
| } |
| public int getLineNumber() { |
| return IMessage.LINENO_UNSET; |
| } |
| public int getOffset() { |
| return IMessage.OFFSET_UNSET; |
| } |
| public int getLength() { |
| return IMessage.OFFSET_UNSET; |
| } |
| public boolean includes(int index) { |
| return false; |
| } |
| public boolean touches(int index) { |
| return index == 0; // ??? |
| } |
| @Override |
| public boolean equals(Object o) { |
| if (o == this) { |
| return true; |
| } |
| if ( ! (o instanceof TextRange)) { |
| return false; |
| } |
| TextRange r = (TextRange) o; |
| return (r.getOffset() == 0) |
| && (r.getLength() == 0); |
| } |
| @Override |
| public int hashCode() { |
| return 0; |
| } |
| @Override |
| public String toString() { |
| return "TextRange.Empty"; //$NON-NLS-1$ |
| } |
| } |
| |
| } |